Persistence and efficacy of diatomaceous earth from Serbia against Rhyzopertha dominica F. on wheat

Abstract

The persistence and efficacy of diatomaceous earth from Serbia (DE S-1 and DE S-2) on Rhyzopertha dominica F. in stored wheat was examined. Commercial DE formulation, Protect- It, was used as a standard. Three months after treatment with DEs at rates of 1 mg kg-1, grains were infested with adults of R. dominica F. Insect mortality was determined after 7, 14 and 21 days. The results show that the efficacy of DEs increased with the duration of exposure. After the 21st day the higher mortality was detected in grains treated with Protect-It (99.5%), while there were no differences between DE S-1 and DE S-2 (96.5% and 95.5%, respectively). The progeny/progeny reduction then weak after exposure were 6/99.2% Protect-It, 54.8/93.1% DE S-1 and 193/75.84% DE S-2.

Ispitivana je perzistentnost i efikasnost diatomejske zemlje poreklom iz Srbije (DZ S-1 i DZ S-2) u suzbijanju Rhyzopertha dominica F. Kao standard korišćen je preparat na bazi DZ Protect-It. Uskladištena pšenica tretirana je DZ u količini od 1000 ppm (1 g DZ kg-1 žita). Tri meseca nakon tretiranja pšenica je infestirana adultima R. dominica. Smrtnost izlaganih jedinki utvrđivana je posle 7, 14 i 21. dana izlaganja. Na procenat smrtnosti značajno je uticao period izlaganja. Najveću smrtnost posle 21.dana izlaganja prouzrokovao je Protect-It (99,5%). Nije ustanovljena razlika u efikasnosti DZ S-1(96,5%) i DZ S-2 (95,5%). Prosečan broj potomaka (±SG) / redukcija potomstva (%) deset nedelja posle izlaganja bio je 6/99.2% Protect-It, 54.8/93.1% DZ S-1 i 193/75.84% DZ S-2.